One known type of sliding sunroof has front and rear sliding roofs. Such a sliding sunroof, typically referred to as a double sliding sunroof, includes linkages which move the front and rear sliding roofs separately on a pair of guide rails. In more detail, one of the linkages first pushes the rear sliding roof up and moves it under a fixed roof and then the other linkage tilts the front sliding roof up and moves it over the fixed roof. Such a sliding sunroof is disclosed by Japanese Utility model Application No. 61(1986)-136670, entitled "Sunroof Apparatus," filed on Sep. 8, 1986 and laid open as Japanese Unexamined Utility Model Publication No. 63(1988)-43820 on Mar. 24, 1988.
Since, in the sunroof apparatus described in this publication, the front sliding roof and rear sliding roof are moved backward over and under the fixed roof, respectively, on the same pair of guide rails by the respective linkages, the front sliding roof cannot be opened with the rear sliding roof closed until the rear sliding roof has first been opened. Furthermore, since each guide rail of the pair of guide rails partly extends under the fixed roof, the linkage, which is connected to front part of the front sliding roof, must be disposed in front of the front edge of the fixed roof when the front sliding roof has opened over the fixed roof, and the sunroof is not able to be opened to its full extent.